Three Core and Earth is the type of cable that is typically used for two way lighting , or other applications needing a permanent and switched Live as well as a neutral , as needed in some lighting, central heating controllers and timers on extractor fans. Comprising of three sheathed Conductors Brown,Black and Grey, and a bare Earth which is of the CPC type (Circuit Protective Conductor).

The 2.5mm Conductors are Solid with the CPC earth being 1.5mm also, and rated in normal conditions at around 20 Amps.

Not suitable for unprotected use outside as the outer sheath are vunerable to attack from UV, however Alkyd paint is enough to protect it from UV.